These tips cover the problems of orchid lighting. Lighting problems are frequently encountered by beginners as they are among the most difficult to resolve.
- Orchids generally thrive with as much indirect light as you can provide. Especially in summer, do not expose orchids to direct light, as they can sunburn quickly. A good method to test whether an orchid is properly lighted is to feel the leaves. If they are hot, the light is too strong and they will form black burn spots. Move the plant away from the window, or move to a shady spot on the window sill. Another method to test light intensity is to look at leaf color – if the foliage is a rich dark green, it's probably not receiving enough light. Orchid leaves will be a light green color when they are receiving adequate light. Keep in mind that the more heat and light your orchid receives, the more air circulation the plant requires, and the more water the orchid will need.
- As the sunlight softens in the fall months, slowly increase your orchids light exposure by moving them closer to windows or adjusting filtering curtains. During the winter months, try to give your orchids as much sun as possible, include direct sunlight in the mornings and late afternoon, so they will be encouraged to bloom. As the days grow longer in springtime, watch for signs of redness in leaf color, which indicates that the foliage is approaching its maximum light tolerance. Then slowly decrease light exposure by moving the orchids away from windows or adjusting your filter curtains to provide more shade.
- To keep your orchids prominently displayed in your windowsills, use sheer curtains to control the amount of light reaching the plants. Thicker curtain fabrics or fabrics with patterns will reduce light intensity for summer, sheerer curtains allow more light to pass through for spring and fall. Curtain patterns and pleats will create alternate bands of light and shade, which simulates the natural environment orchids enjoy in trees. Since orchids thrive with strong, indirect light, the same filtering fabrics that protect your orchids will also provide good light levels in your home!
- Turn your orchids periodically to provide even lighting and encourage even growth. Monopodial plants (such as Vandas and phalaenopsis) should be turned 180 degrees about once a month. Sympodial orchids (such as Cattleyas and Oncidiums) should be turned 90 degrees left and then 180 degrees right, successively, to keep their growth upright. Turn sympodials about once a week except when they begin to bloom. While blooming, do not turn the plants or the blooms may develop slightly twisted as they attempt to follow the light. After blooms have fully emerged, start the turning sequence again.
- Individual orchids, even those of the same type, respond differently to light. If your orchids are inexplicably languishing, try moving your plants around to positions with different light intensity. If you have an orchid that is not blooming, try moving it to a sunnier area, especially if the leaves are darker green than the leaves on your blooming orchids. If your orchid leaves are turning yellow, it may be from excess light – move it back from the windowsill or try a filtering curtain to reduce light intensity. In late spring to early fall, you can move your orchids outside, hanging them from tree branches where they will receive good indirect light or light filtered through the leaves of the trees. Do not be afraid to experiment avoiding the extremes of strong direct sunlight or substantive shade.